US1937129A - Brake shoe - Google Patents

Description

Nov. 28, 1933. F. w. sARGl-:NT 1,937,129

BRAKE SHOE Filed March '7, A1931 2 Sheets-Sheet 2 Patented Nov. Y 28, 1933 BnAKE SHOE Fitz William Sargent, MahwahjN.l J., assigner to The American Brake AShoeand-'Foundry .1, Company, Wilmington, Del., a corporation of y Delaware Appncation March V"1, y1,931., o serial*k No. i 520,878'

3l Claims.

A This invention relates to improvements in brake shoes and its Objectis to reduce the vibration and relative movement ofthe shoe on the head and-thereby avoid the wear of contacting parts incident to such vibration and movement; and also tohold the shoe tightly on the head` and thereby reduce the liability of fractureand better ensure holding the parts together -in case of fracture to prolong ythe life and service of the shoe. o o

Brakev heads arey usually lmade of malleable iron or mild steel which are tough and strong metals and resist tensional and torsional stresses, but because of the comparative softness of these A metals they willabrade by rubbing contact so that in the course of time the parts ofthe head which. support the shoev will wear and loosen ther mounting andreduce the emciency thereof and increase the liability. of the shoe and head to v fracture, requiring replacement before the head or the shoe has otherwise reached its limit of service. rThe vibration of the shoe and the head -in service is largely the cause of wear `of parts and this is increased materially as wear produces ;26 looseness in the mounting and particularly when head when the brake is not in action and when the brake is being applied. If the key holds the shoe looselyvon the headwhen the brake is not in action, the shoe will hang more or less free on the head and will move andl rattle around on the head causing excessive wear of the brake head-'lug on which the shoey rests as wellas on the attaching lug, due to the vibration of the-shoe and head when the car on which they are mounted is .moving and especially during switching 4o operations; and this wearing action: increases rapidly as the shoe becomes looser on the head andpermits av slight bending of the `reenforcing back in the shoe. when the body of the'shoe fractures, finally resulting in the back breaking and permitting parts of the body to fall away and' consequent premature destruction Aof the shoe. v

My invention aims to reduce the relative movement of the shoe'and head and thereby prevent 0 the excessive wear of their contacting parts and the damage to the shoe and the headwhich resultstherefrom, thereby prolonging the life of the shoe and thehead and increasing the emciency of the shoe.

vThe invention is adapted for heads and shoes of different' types, including flanged and un- Ilanged shoes, and I Vhave selected to illustrate the invention a simple type of car shoe in the accompanying drawings in which Fig. 1 is a side elevation of a shoe partly in (criss-24:9)r .l

section mounted on a head which is partlyvbroken away.

Fig. 2 is a shoeon the line 2--2 of Fig. 1.

' Fig.,3 is a transverse sectional viewof shoe and head. on the line 3-(3 of Fig. 1.

Fig. 4 is a vfragmentary view showing another embodiment of the invention.

Fig. 5 is a transversesectional'view'of the `shoe on the line 5-5 of Fig. 4;

Fig. 6 shows another embodiment `of the.in

vention.

Fig. 7 is a transverse` sectional viewof Vthe shoe v on'the'line 'If-J7 ofFig. 6. Fig. 8 shows another embodiment of theinvention. q w

y Fig. 9 is` a transverse sectionalviewof the shoe on. the line 9-9 offFig. 8. i j a 'Referring to the drawings they shoe lois-provided with end lugs 9, anattaching lug `11 and a suitable reenforcing back 12. The head 13 has two lugs 14spaced apart to receive the attaching lug 11 ofthe shoe.- The lug-11 andthe lugs 14 have openings 11 and 14 respectivelyextending lengthwise of the shoe and head and constituting keyways to receive the key 15. .Provisionis made vfor ,c1.istomary clearance between the lugsj 11 and v14 ofthe shoe and the head, which are castings,

the..

.PATENT ,OFFICE';

transverse sectional .view ofgtheu Y Aand the openings in the lugs are made by the use y Y ofr cores without machining.r` Thereis'generally some looseness of Alit betweenothe shoe and the head and while the key will hold the 'shoe on the head it will not always hold it tightly andv because of the clearance loetweenthe lugs'andY the vibrations in service the lug of the shoe ywillvvearo'n the lugl of the head upon which it rests and sooner or later cause vsuch an excessive'looseness in the mounting of the-shoeon' the head that damage Ato theshoe will result'. ToY avoid these disadvantages the shoe is provided with bossesl spaced from the attaching lug 11 to receive the headlu'gs 14 between themselves and the attaching lug,V

Fig. 1. The bosses should be located close tothe headv lugs and should project slightlybeyond the outer walls'of the openings 14' inthe head lugs when the shoe is mounted on the head and they are preferably rounded as shown.V It is understood, of course, V that a brake head and a brake shoe are hung' in a substantially upright y position and when the key is driven inplace in the openings in the lugs it will bear upon the Itop bossv 16, the outer wall of theopening'in the topiherad lug,-the outer wall of' the opening in the 'shoe' lug, v the outer wall of the opening in the bottom .head

parts correspondingly reduced. I prefer to provide two bosses'to make the shoe interchangeable end for end and because twojbosses will more effectively Wedge the key in the lugs than one boss but for some purposes and with someshoes and headsone vboss may be suicient. Ink Figs.V`

1-3 the bosses are shownv as formed by the body metal of the shoe but separate bosses may be cast in the body of the shoe as lshown. at 1"(Y inligfs.v 4

and 5; or the bosses may bei formed by Vbending,

11p-a part 18 of the reenforcing back, 19 and'extending the body metal to form a support 20 therefor, Figs. 6 and '7, and this body'metal sup- Y port may be omitted from the supportas shown at 21, Figs. 8 and 9. When the inner' side 'of the brake head is curved,V the end of the key will be defiected-ther'eby toits final position as shown in Fig. l but for other types of heads it may be Adesirable l.to provide`v a projection forming an inclined `bearing 22 on the head for this purpose. -Th'e bossl has'aV face 23 substantially perpendicularto the back of the shoe andan outer face 24iwhich-inclines to the back of the body and toward the end of the shoe. f This. inclined face will' guide the end of the key when it is being inserted to fasten the shoe on the head. e The invention'provides a simple" and effective `means for ensuring that the key will hold the shoe tightly on the head to` prevent a freedom of movement lof the shoe on the head .which will produce .'excessive wear of contacting parts.

Sometimes the lower lug of the head Which carrieslthe weight ofthe .shoe will be almost completely worn away, and in such case the lug on the shoe is Vsubjected to excessive Wear. This will be-better .understoo'dwhen' it is realizedthat the aver- Y Yage life of a brake shoe is from four to' five years after it is mounted'on its brake head.'l The wear on the lugs *frequently` becomes excessive long before the body of the shoe has reached its limit of wear and the looseness of iit between the shoe f and the headdue to excessive 'wear of the lugs and the resulting increase in the magnitude'of 'the vibrations between the shoe and the head Y to whichthe shoe is subjected in service, and the violence of these vibrations; results in fracture of thebody'ofthelshoe and loosening ofthe parts ofthe fractured body so that some of themare -liableto fall away from the back; and also results in subjecting the back to greater and more violent vvibrations which cause it to r break and fall away from the shoe with whateverpart or parts of thebody that may be attached thereto. Ihefbosses.alsov function toholdthe shoe in its Aproper positionon the head by co-operating with the Vlugs to prevent excessive relative movement of the shoe on the head. This isnally effected by the wedging position ofthe key in the lugs but the bosses co-'operate with the key to a material y extent in preventing excessive movement ofthe shoev relative'to the head. I do not intend to be understood as meaning that the invention will hold the shoe rigidlyon .the head because I know thatconditions of manufacture will not permit theaccuracy of t ywhich would be necessary to prevent some relative movement under the condivention will materially limit the extent of such movement and correspondingly reduce the wear of contacting parts and eliminate the liability of excessive wear and the damage and danger which may result therefrom. Y

I have shown the invention in simple embodie Y` ments which I believe will be sufcient forafull lunderstanding thereof, but I do not limit the invention to these particular embodiments and I may make changes in the form,` construction and arrangement of .parts to adapt the invention to diiferent conditions'within the scope of the followingk claims: Y

, I claim:

spaced. lugs thereon, a brake Vshoe having Y'end lugs, an attaching lug onthe brake vshoe`-posi tioned between the lugsvon the head, said head lugs and attaching lug having openings :therein forming akeyway, bosses on the shoe be.-

tween the end lugs and the attaching lug, 'the' faces of said bosses opposite said attaching lug being substantially perpendicular to'the back` vof the shoe and the outer vfaces, ofthe bosses lugs'therebetween and to restrict relative end# Y t Wise ,movement of the shoe and head, and 'a fastening'key arranged in said keyway', 'said' key bearing against the outer wall ofy the opening in the attaching lug and the outer wall of the openings in the headlugs and engagingvthe bosses and-being deected thereby in said lugs totightly fasten the shoe on the head and to hold the ends of the key clear ofthe --end lugs on the' shoe. f

2. The combination ofabrake head 'having spaced lugs thereon, a brake 'shoe comprisingY a vbedy having end lugs anda central attaching lugrsaid head lugs 'and attaching lug having Aopenings therein forming a keyway, a'reen'forced vback embedded in the"body, parts ofthe back being ldistorted to formbosses on the shoe between the end lugsand the attaching` lug,` said attaching lug andbosses 'cooperating to receive the head llugs therebetween and to restrict rela'- tive endwise movement of the shoe and head, and a fasteningkeyfarranged in saidkeyW'ay, said key bearing against the outer 'wall of thejopening inthe attaching lug and the outer-Wall--of the openings in 'the head'lugsl and engagingV the bosses and being deflected thereby in said *lugs to tightly fasten theshoel on the head -an'd to hold the ends ofthe key vclear of the end lugs on the shoe. `A3. The combination of a brakeheadfhav'ing spaced lugs thereon, anda brake shoe V.having anattaching lug adapted to be arranged between the lugs on the head, said lugs, having openings thereinY forming a keyway, bossescn the shoe spaced from the attaching lug/on opposite sides thereof to receive thek lugs, onnthe head between themselves and the attaching lug, axfastening key arranged in said key'way, and a,l projection on the head orming'an'inclinedv bearing to be engagedV byl and to direct the end ofv the key when driven inthe keyway, said key bearing-on said bosses' and against the outer wall of the opening in` the attaching lug` andthe outer wall of the openings.- in the head lugs and being def `ilected thereby to tightlyrfasten thershoe on thehead, l Y l l FITZ WILLIAM- SARGEN'IBP iso its

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